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Detection rules › Sigma

ScreenConnect - SlashAndGrab Exploitation Indicators

Status
test
Severity
high
Log source
product windows, category file_event
Author
Nasreddine Bencherchali (Nextron Systems)
Source
github.com/SigmaHQ/sigma

Detects indicators of exploitation by threat actors during exploitation of the "SlashAndGrab" vulnerability related to ScreenConnect as reported Team Huntress

MITRE ATT&CK coverage

TacticTechniques
StealthNo specific technique

Event coverage

ProviderEventTitle
SysmonEvent ID 11FileCreate

Rule body yaml

title: ScreenConnect - SlashAndGrab Exploitation Indicators
id: 05164d17-8e11-4d7d-973e-9e4962436b87
status: test
description: |
    Detects indicators of exploitation by threat actors during exploitation of the "SlashAndGrab" vulnerability related to ScreenConnect as reported Team Huntress
references:
    - https://www.huntress.com/blog/slashandgrab-screen-connect-post-exploitation-in-the-wild-cve-2024-1709-cve-2024-1708
author: Nasreddine Bencherchali (Nextron Systems)
date: 2024-02-23
tags:
    - detection.emerging-threats
    - attack.stealth
logsource:
    product: windows
    category: file_event
detection:
    selection:
        - TargetFilename|contains|all:
              - 'C:\Windows\Temp\ScreenConnect\'
              - '\LB3.exe'
        - TargetFilename|contains:
              - 'C:\mpyutd.msi'
              - 'C:\perflogs\RunSchedulerTaskOnce.ps1'
              - 'C:\ProgramData\1.msi'
              - 'C:\ProgramData\Microsoft\Windows\Start Menu\Programs\Startup\mpyutd.msi'
              - 'C:\ProgramData\update.dat'
              - 'C:\Users\oldadmin\Documents\MilsoftConnect\Files\ta.exe'
              - 'C:\Windows\Help\Help\SentinelAgentCore.dll'
              - 'C:\Windows\Help\Help\SentinelUI.exe'
              - 'C:\Windows\spsrv.exe'
              - 'C:\Windows\Temp\svchost.exe'
    condition: selection
falsepositives:
    - Unknown
level: high

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    - TargetFilename|contains|all:
          - 'C:\Windows\Temp\ScreenConnect\'
          - '\LB3.exe'
    - TargetFilename|contains:
          - 'C:\mpyutd.msi'
          - 'C:\perflogs\RunSchedulerTaskOnce.ps1'
          - 'C:\ProgramData\1.msi'
          - 'C:\ProgramData\Microsoft\Windows\Start Menu\Programs\Startup\mpyutd.msi'
          - 'C:\ProgramData\update.dat'
          - 'C:\Users\oldadmin\Documents\MilsoftConnect\Files\ta.exe'
          - 'C:\Windows\Help\Help\SentinelAgentCore.dll'
          - 'C:\Windows\Help\Help\SentinelUI.exe'
          - 'C:\Windows\spsrv.exe'
          - 'C:\Windows\Temp\svchost.exe'

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
TargetFilenamematch
  • C:\ProgramData\1.msi
  • C:\ProgramData\Microsoft\Windows\Start Menu\Programs\Startup\mpyutd.msi
  • C:\ProgramData\update.dat
  • C:\Users\oldadmin\Documents\MilsoftConnect\Files\ta.exe
  • C:\Windows\Help\Help\SentinelAgentCore.dll
  • C:\Windows\Help\Help\SentinelUI.exe
  • C:\Windows\Temp\ScreenConnect\
  • C:\Windows\Temp\svchost.exe
  • C:\Windows\spsrv.exe
  • C:\mpyutd.msi
  • C:\perflogs\RunSchedulerTaskOnce.ps1
  • \LB3.exe